1. Field of the Invention
The present invention relates to a flat primary battery, a negative electrode mixture for flat primary battery, and a method for manufacturing a flat primary battery.
2. Description of the Related Art
With the advance of high performance and price reduction in small-sized electronic equipment, flat primary batteries such as coin-shaped batteries and button-shaped batteries, which are used for small-sized electronic equipment such as electronic wrist watches and portable electronic calculators, are required to achieve, in addition to the advance of high performance and price reduction, an enhancement of the productivity.
As such a flat primary battery, alkaline button batteries using manganese dioxide for a positive electrode and a zinc powder in a gel state for a negative electrode, silver oxide batteries using silver oxide for a positive electrode and a zinc powder in a gel state for a negative electrode, and the like are known. These batteries are formed by caulking a positive electrode can filled with a positive electrode mixture and a negative electrode can filled with a negative electrode mixture via a separator.
In such a flat primary battery, a ratio of an active material in the positive electrode mixture or negative electrode mixture is adjusted depending upon an electric capacity required for the size of each battery. In the negative electrode mixture in a gel state using zinc or a zinc alloy, the ratio of the active material is adjusted by including an insulating powder of a non-metal which does not react with an electrolytic solution (see, for example, Patent Document 1). Patent Document 1: JP-A-2010-044906